We designed this study in order to investigate the prevalence of calcium and phosphate disturbances and their correlates with other markers such as fetuin-A, uc-MGP and FGF-23, vascular calcification on EBCT and functional parameters of arterial stiffness.Secondly, we want to optimize the application of the CAC score in this population, where classical contrast agents are contra-indicated, by adding serological and or functional parameters to this score. Thirdly, we aim to study the prognostic role of all these parameters.